<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=US-ASCII">
<title>Singles</title>
<link rel="previous" href="towers.html">
<link rel="ToC" href="index.html">
<link rel="up" href="index.html">
<link rel="index" href="docindex.html">
<link rel="next" href="magnets.html">
<style type="text/css">body { word-wrap: break-word; } body.night { color: #dddddd; background: #000000; } body.night a:link { color: #8888ff; } body.night a:visited { color: #cc88ff; }</style></head>
<body>
<p><a href="towers.html">Previous</a> | <a href="index.html">Contents</a> | <a href="docindex.html">Index</a> | <a href="magnets.html">Next</a></p>

<ul>
<li><a href="#C32">Chapter 32: Singles</a>
<ul>
<li><a href="#S32.1">32.1 Singles controls</a></li>
<li><a href="#S32.2">32.2 Singles parameters</a></li>
<li><a href="#S32.3">32.3 Singles user preferences</a></li>
</ul></li>
</ul>
<h1><a name="C32"></a>Chapter 32: <a name="i0"></a>Singles</h1>
<p>
You have a grid of white squares, all of which contain numbers. Your task is to colour some of the squares black (removing the number) so as to satisfy all of the following conditions:
</p>
<ul><li>
No number occurs more than once in any row or column.
</li>
<li>
No black square is horizontally or vertically adjacent to any other black square.
</li>
<li>
The remaining white squares must all form one contiguous region (connected by edges, not just touching at corners).
</li>
</ul>
<p>
Credit for this puzzle goes to <a name="i1"></a>Nikoli <a href="#p0">[15]</a> who call it <a name="i2"></a>Hitori.
</p>
<p>
Singles was contributed to this collection by James Harvey.
</p>
<p><a name="p0"></a>
[15] <a href="https://www.nikoli.co.jp/en/puzzles/hitori/"><code>https://www.nikoli.co.jp/en/puzzles/hitori/</code></a>
</p>
<h2><a name="S32.1"></a>32.1 <a name="i3"></a>Singles controls</h2>
<p>
<em>On Android, please touch for left click and long press for right click. Also note that where this manual refers to pressing a letter on the keyboard, the Android version has icons at the bottom of the screen instead (Control and Shift are not available). There is also an optional "Night mode" which uses darker colours in low light.</em>
</p>
<p>
Left-clicking on an empty square will colour it black; left-clicking again will restore the number. Right-clicking will add a circle (useful for indicating that a cell is definitely not black). Clicking outside the grid will toggle whether black squares completely hide the numbers on them, or display them in dark grey.
</p>
<p>
You can also use the cursor keys to move around the grid. Pressing the return or space keys will turn a square black or add a circle respectively, and pressing the key again will restore the number or remove the circle.
</p>
<p>
(All the actions described in <a href="common.html#S2.1">section 2.1</a> are also available.)
</p>
<h2><a name="S32.2"></a>32.2 <a name="i4"></a>Singles parameters</h2>
<p>
These parameters are available from the &#8216;Custom...&#8217; option on the &#8216;Type&#8217; menu.
</p>
<dl><dt>
<em>Width</em>, <em>Height</em>
</dt>
<dd>
Size of grid in squares.
</dd>
<dt>
<em>Difficulty</em>
</dt>
<dd>
Controls the difficulty of the generated puzzle.
</dd>
</dl>
<h2><a name="S32.3"></a>32.3 <a name="i5"></a>Singles user preferences</h2>
<p>
On platforms that support user preferences, the &#8216;Preferences&#8217; option on the &#8216;Game&#8217; menu will let you configure whether numbers on black squares are visible. Unlike clicking outside the grid, this will persist between games.
</p>

<hr><address></address></body>
</html>
